css/CSS2/zindex/z-index-dynamic-001.xht

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

 <head>

  <title>CSS Test: Z-index - dynamically setting z-index to bring an element from back to in front of</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" />
  <link rel="help" title="Section 9.9.1 Specifying the stack level: the 'z-index' property" href="http://www.w3.org/TR/CSS21/visuren.html#z-index" />
  <link rel="match" href="../reference/ref-filled-green-100px-square.xht" />
  <meta http-equiv="Content-Script-Type" content="text/javascript" />
  <meta content="dom" name="flags" />
  <meta content="Setting the 'z-index' property of a positioned element can bring it from behind the surface on a lower stack level to a greater stack level passing it in front of another element painted on the surface." name="assert" />

  <style type="text/css"><![CDATA[
  #test
  {
  background-color: green;
  display: block;
  z-index: -1;
  }

  #red-layer
  {
  background-color: red;
  top: -100px;
  z-index: auto;
  }

  #test, #red-layer
  {
  height: 100px;
  position: relative;
  width: 100px;
  }
  ]]></style>

  <script type="text/javascript"><![CDATA[
  function fromBottomToTopOfStack()
  {
  document.getElementById("test").style.zIndex = 1;
  }
  ]]></script>

 </head>

 <body onload="fromBottomToTopOfStack();">

  <p>Test passes if there is a filled green square and <strong>no red</strong>.</p>

  <div><span id="test"></span></div>

  <div id="red-layer"></div>

 </body>
</html>